1. Field of the Invention
The present invention relates to a speaker.
2. Description of the Related Art
When a speaker(s) is installed in a personal computer or multimedia portable apparatus, for example, it is usual for a pair of speakers to be installed in elongated areas at right and left sides of a video screen of the personal computer or multimedia portable apparatus, or for a single speaker to be installed in another elongated area under the video screen. Thus, it is desirable that the shape of such a speaker be an elongated shape, such as a rectangular shape, an elliptic shape, or the like.
For example, a conventional speaker 1200 is described in Japanese Laid-Open Publication No. 10-191494. Hereinafter, the conventional speaker 1200 is described with reference to FIGS. 12a and 12b. 
FIG. 12a is a plan view of the conventional speaker 1200. FIG. 12b is a cross-sectional view of the conventional speaker 1200 taken along line A-Axe2x80x2 of FIG. 12a. 
The speaker 1200 includes: a frame 1201; a magnetic circuit 1206 fixed to the frame 1201; a diaphragm 1203, which is fixed to the frame 1201 such that the diaphragm 1203 can vibrate in a direction shown by arrow P of FIG. 12b; a driving force transmitting member 1204 connected to the diaphragm 1203; and dampers 1205 for supporting the driving force transmitting member 1204. An outer perimeter of the diaphragm 1203 is fixed to the frame 1201 via an edge 1202.
One end of each damper 1205 is connected to the driving force transmitting member 1204 above the magnetic circuit 1206. The other end of each damper 1205 is connected to the frame 1201 above the magnetic circuit 1206.
The driving force transmitting member 1204 has a region wherein a voice coil 1207 is formed. When a driving current flows through the voice coil 1207, a driving force is produced in a direction shown by arrow P of FIG. 12b due to an effect produced by the driving current and a magnetic flux supplied by the magnetic circuit 1206. The driving force transmitting member 1204 is configured such that the produced driving force is transmitted to the diaphragm 1203. This transmitted driving force causes the diaphragm 1203 to vibrate in the direction shown by arrow P. As a result, sound is reproduced.
However, the thickness of the conventional speaker 1200 amounts to at least the sum of the thickness of the magnetic circuit 1206, the thickness of the damper 1205, and the thickness of the diaphragm 1203. This is because the damper(s) 1205 is provided above the magnetic circuit 1206.
According to one aspect of the present invention, a speaker includes: a frame; a magnetic circuit fixed to the frame; a diaphragm fixed to the frame so as to be capable of vibrating in a predetermined direction, a driving force transmitting member connected to the diaphragm; and a damper for supporting the driving force transmitting member, wherein the magnetic circuit is positioned between a first plane and a second plane, the first plane being parallel to the diaphragm and defined as a plane with which at least a portion of the magnetic circuit is in contact, and the second plane being parallel to the diaphragm and defined as a plane with which at least a portion of the magnetic circuit is in contact, the driving force transmitting member has a region in which a voice coil is formed, the driving force transmitting member is structured so as to transmit to the diaphragm, a driving force, in the predetermined direction, caused by an effect of an electric current flowing through the voice coil and a magnetic flux generated from the magnetic circuit, and one end of the damper is connected at a position between the first and second planes, and the other end of the damper is connected at another position between the first and second planes.
In one embodiment of the present invention, the magnetic circuit is positioned inside the frame.
In another embodiment of the present invention, the diaphragm has a recessed portion, and the driving force transmitting member is connected to the recessed portion of the diaphragm.
In still another embodiment of the present invention, the frame has a recessed portion, and at least a portion of the magnetic circuit is buried in the recessed portion of the frame.
In still another embodiment of the present invention, the magnetic circuit has a protrusion, and the frame has a portion which connects to the protrusion.
In still another embodiment of the present invention, the magnetic circuit includes a first magnetic circuit portion and a second magnetic circuit portion; the frame includes a first frame plate to which the first magnetic circuit portion is connected, a second frame plate to which the second magnetic circuit portion is connected, a third frame plate, and a fourth frame plate; an end side of the third frame plate is connected to an end side of the first frame plate, and the other end side of the third frame plate is connected to an end side of the second frame plate; and an end side of the fourth frame plate is connected to the other end side of the first frame plate, and the other end side of the fourth frame plate is connected to the other end side of the second frame plate.
In still another embodiment of the present invention, the frame further includes a bottom plate.
In still another embodiment of the present invention, the driving force transmitting member includes at least one through hole outside of a region in which the voice coil is formed.
In still another embodiment of the present invention, the driving force transmitting member is formed by combining a core member having at least one through hole and a surface member having a region in which the voice coil is formed.
In still another embodiment of the present invention, the magnetic circuit includes a first magnetic circuit portion, a second magnetic circuit portion, and a magnetic gap defined by the first and second magnetic circuit portions; the first magnetic circuit portion includes a first magnet having a rectangular parallelepiped shape, a first plate fixed onto an upper surface of the first magnet, and a second plate fixed onto a lower surface of the first magnet; the second magnetic circuit portion includes a second magnet having a rectangular parallelepiped shape, a third plate fixed onto an upper surface of the second magnet and a fourth plate fixed onto a lower surface of the second magnet; a side surface of the first magnetic circuit portion is connected onto the frame, a side surface of the second magnetic circuit portion is connected onto the frame, the first and second magnets face each other such that facing sides thereof have opposite polarities; the magnetic gap includes a first magnetic gap, which is defined by the first and third plates and through which the magnetic flux generated by the first and second magnets passes, and a second magnetic gap, which is defined by the second and fourth plates and through which the magnetic flux generated by the first and second magnets passes.
In still another embodiment of the present invention, the magnetic circuit includes a first magnetic circuit portion, a second magnetic circuit portion, and a magnetic gap defined by the first and second magnetic circuit portions; the first magnetic circuit portion includes a magnet having a rectangular parallelepiped shape, a first plate fixed onto an upper surface of the magnet, and a second plate fixed onto a lower surface of the magnet; the second magnetic circuit portion includes a yoke; a side surface of the first magnetic circuit portion is connected onto the frame, a side surface of the second magnetic circuit portion is connected onto the frame, the magnet and the yoke face each other; the magnetic gap includes a first magnetic gap, which is defined by the first plate and the yoke and through which the magnetic flux generated by the magnet passes, and a second magnetic gap, which is defined by the second plate and the yoke and through which the magnetic flux generated by the magnet passes.
In still another embodiment of the present invention, at least a portion of the first plate is in contact with the yoke which faces the first plate, and at least a portion of the second plate is in contact with the yoke which faces the second plate.
In still another embodiment of the present invention, the magnetic circuit includes a first magnetic circuit portion, a second magnetic circuit portion, and a magnetic gap defined by the first and second magnetic circuit portions; the first magnetic circuit portion includes a first magnet having a rectangular parallelepiped shape, a second magnet having a rectangular parallelepiped shape, a first plate, and a second plate; the second magnetic circuit portion includes a yoke; a side surface of the first plate is connected onto the frame, the opposite side surface of the first plate is connected onto the first magnet, a side surface of the second plate is connected onto the frame, the opposite side surface of the second plate is connected onto the second magnet, the first magnet and the yoke face each other, and the second magnet and the yoke face each other; the first and second magnets are aligned along a predetermined direction such that facing sides thereof have opposite polarities; and the magnetic gap includes a first magnetic gap, which is defined by the first plate and the yoke and through which the magnetic flux generated by the first magnet passes, and a second magnetic gap, which is defined by the second plate and the yoke and through which the magnetic flux generated by the second magnet passes.
In still another embodiment of the present invention, a speaker includes: a frame; a magnetic circuit fixed to the frame; a diaphragm fixed to the frame so as to be capable of vibrating in a predetermined direction; a driving force transmitting member connected to the diaphragm; and a damper for supporting the driving force transmitting member, wherein the magnetic circuit is positioned between a first plane and a second plane, the first plane being parallel to the diaphragm and defined as a plane with which at least a portion of the magnetic circuit is in contact, and the second plane being parallel to the diaphragm and defined as a plane with which at least a portion of the magnetic circuit is in contact, the driving force transmitting member has a region in which a voice coil is formed, the driving force transmitting member is structured so as to transmit to the diaphragm, a driving force, in the predetermined direction, caused by an effect of an electric current flowing through the voice coil and a magnetic flux generated from the magnetic circuit, the magnetic circuit includes a first magnetic circuit portion, a second magnetic circuit portion, and a magnetic gap defined by the first and second magnetic circuit portions, the first magnetic circuit portion includes a magnet having a rectangular parallelepiped shape, a first plate fixed onto an upper surface of the magnet, and a second plate fixed onto a lower surface of the magnet, the second magnetic circuit portion includes a yoke, a side surface of the first magnetic circuit portion is connected onto the frame, a side surface of the second magnetic circuit portion is connected onto the frame, the magnet and the yoke face each other, and the magnetic gap includes a first magnetic gap, which is defined by the first plate and the yoke and through which the magnetic flux generated by the magnet passes, and a second magnetic gap, which is defined by the second plate and the yoke and through which the magnetic flux generated by the magnet passes.
In one embodiment of the present invention, at least a portion of the first plate is in contact with the yoke which faces the first plate, and at least a portion of the second plate is in contact with the yoke which faces the second plate.
In still another embodiment of the present invention, a speaker includes: a frame; a magnetic circuit fixed to the frame; a diaphragm fixed to the frame so as to be capable of vibrating in a predetermined direction; a driving force transmitting member connected to the diaphragm; and a damper for supporting the driving force transmitting member, wherein the magnetic circuit is positioned between a first plane and a second plane, the first plane being parallel to the diaphragm and defined as a plane with which at least a portion of the magnetic circuit is in contact, and the second plane being parallel to the diaphragm and defined as a plane with which at least a portion of the magnetic circuit is in contact, the driving force transmitting member has a region in which a voice coil is formed, the driving force transmitting member is structured so as to transmit to the diaphragm, a driving force, in the predetermined direction, caused by an effect of an electric current flowing through the voice coil and a magnetic flux generated from the magnetic circuit, the magnetic circuit includes a first magnetic circuit portion, a second magnetic circuit portion, and a magnetic gap defined by the first and second magnetic circuit portions, the first magnetic circuit portion includes a first magnet having a rectangular parallelepiped shape, a second magnet having a rectangular parallelepiped shape, a first plate, and a second plate, the second magnetic circuit portion includes a yoke, a side surface of the first plate is connected onto the frame, the opposite side surface of the first plate is connected onto the first magnet, a side surface of the second plate is connected onto the frame, the opposite side surface of the second plate is connected onto the second magnet, the first magnet and the yoke face each other, and the second magnet and the yoke face each other, the first and second magnets are aligned along a predetermined direction such that facing sides thereof have opposite polarities, and the magnetic gap includes a first magnetic gap, which is defined by the first plate and the yoke and through which the magnetic flux generated by the first magnet passes, and a second magnetic gap, which is defined by the second plate and the yoke and through which the magnetic flux generated by the second magnet passes.
Thus, the invention described herein makes possible the advantage of: (1) providing a speaker which is thinner, by at least the thickness of the damper, than a conventional speaker which has the damper above a magnetic circuit; and (2) providing a magnetic circuit which further improves the driving efficiency of a speaker.
This and other advantages of the present invention will become apparent to those skilled in the art upon reading and understanding the following detailed description with reference to the accompanying figures.